Improving stability in south-western NSW RIT-T – Project Specification Consultation Report Region: South Western New South Wales Date of issue: 31 July 2020 Disclaimer This suite of documents comprises TransGrid’s application of the Regulatory Investment Test for Transmission (RIT-T) which has been prepared and made available solely for information purposes. It is made available on the understanding that TransGrid and/or its employees, agents and consultants are not engaged in rendering professional advice. Nothing in these documents is a recommendation in respect of any possible investment. The information in these documents reflect the forecasts, proposals and opinions adopted by TransGrid as at July 2020 other than where otherwise specifically stated. Those forecasts, proposals and opinions may change at any time without warning. Anyone considering information provided in these documents, at any date, should independently seek the latest forecasts, proposals and opinions. These documents include information obtained from the Australian Energy Market Operator (AEMO) and other sources. That information has been adopted in good faith without further enquiry or verification. The information in these documents should be read in the context of the Electricity Statement of Opportunities, the Integrated System Plan published by AEMO and other relevant regulatory consultation documents. It does not purport to contain all of the information that AEMO, a prospective investor, Registered Participant or potential participant in the National Electricity Market (NEM), or any other person may require for making decisions. In preparing these documents it is not possible, nor is it intended, for TransGrid to have regard to the investment objectives, financial situation and particular needs of each person or organisation which reads or uses this document. In all cases, anyone proposing to rely on or use the information in this document should: 1. Independently verify and check the currency, accuracy, completeness, reliability and suitability of those information 2. Independently verify and check the currency, accuracy, completeness, reliability and suitability of reports relied on by TransGrid in preparing these documents 3. Obtain independent and specific advice from appropriate experts or other sources. Accordingly, TransGrid makes no representations or warranty as to the currency, accuracy, reliability, completeness or suitability for particular purposes of the information in this suite of documents. Persons reading or utilising this suite of RIT-T-related documents acknowledge and accept that TransGrid and/or its employees, agents and consultants have no liability for any direct, indirect, special, incidental or consequential damage (including liability to any person by reason of negligence or negligent misstatement) for any damage resulting from, arising out of or in connection with, reliance upon statements, opinions, information or matter (expressed or implied) arising out of, contained in or derived from, or for any omissions from the information in this document, except insofar as liability under any New South Wales and Commonwealth statute cannot be excluded. Privacy notice TransGrid is bound by the Privacy Act 1988 (Cth). In making submissions in response to this consultation process, TransGrid will collect and hold your personal information such as your name, email address, employer and phone number for the purpose of receiving and following up on your submissions. Under the National Electricity Law, there are circumstances where TransGrid may be compelled to provide information to the Australian Energy Regulator (AER). TransGrid will advise you should this occur. TransGrid’s Privacy Policy sets out the approach to managing your personal information. In particular, it explains how you may seek to access or correct the personal information held about you, how to make a complaint about a breach of our obligations under the Privacy Act, and how TransGrid will deal with complaints. You can access the Privacy Policy here (https://www.transgrid.com.au/Pages/Privacy.aspx). 2 | Improving stability in south-western NSW RIT-T – Project Specification Consultation Report Executive summary TransGrid is applying the Regulatory Investment Test for Transmission (RIT-T) to options for improving stability in the south-western New South Wales (NSW) power system. Publication of this Project Specification Consultation Report (PSCR) represents the first step in the RIT-T process. The main power system in south-western NSW consists primarily of one 330 kV transmission line from Darlington Point to Wagga Wagga (Line 63) and 220 kV transmission lines west of Darlington Point (including Line X5). Smaller underlying 132 kV transmission lines supply regional towns. This area has seen significant growth in renewable connections to the transmission network as part of the wider energy market transition. Approximately 560 MW of renewable generation has connected in the area since December 2015, with a further 800 MW expected to connect by 2021. This is having an impact on how this part of the power system operates. In particular, while power has historically primarily flowed west from Darlington Point to supply rural and mine loads, this is expected to reverse with the increase in renewable generation in the area, particularly during daytime when there is an abundance of solar generation. These changes in power flows are expected to lead to an increasing risk of power system instability going forward. Currently, the only way of managing this risk is to constrain generation in south-western NSW. In recognition of the risks to future power system stability, the Australian Energy Market Operator (AEMO) recently implemented an operational constraint in the NEM Dispatch Engine (NEMDE) to limit power flows and prevent this occurring. TransGrid has identified the opportunity to strengthen the transmission network to relieve this constraint and realise net market benefits. This RIT-T has therefore been initiated to progress and consult on the assessment of investment options. The investments considered in this RIT-T are not expected to form part of AEMO’s final 2020 Integrated System Plan (ISP), and so are being progressed outside of the ISP framework. TransGrid’s revenue determination for the 2018-2023 regulatory control period includes a contingent project to support South Western NSW for renewables. This contingent project is to reinforce the transmission network in the area to enable additional renewable generation and provide net market benefits to NSW as well as the wider National Electricity Market.1 The ‘identified need’ is to provide net benefits to the market through relieving the recently imposed generation constraint in the south-western NSW power system The identified need for this RIT-T is to increase overall net market benefits in the National Electricity Market (NEM) through relieving existing and forecast constraints on generation connecting to the transmission network in south-western NSW. Doing so will enable greater output from renewable generation in this region of the NEM. Within the context of the RIT-T assessment, greater output from renewable generation is expected to deliver market benefits primarily through: > reductions in total dispatch costs (including fuel costs), by enabling low cost renewable generation to displace higher cost conventional generation elsewhere; and > reducing the need for new investment in generating plant, or a deferral of generation investment. It is expected that the market benefits from relieving these constraints will exceed the cost of doing so. 1 TransGrid, Revised Regulatory Proposal 2018/19-2022/23, available at: https://www.aer.gov.au/system/files/TransGrid%20- %20Revenue%20Proposal%2018_19%20to%2022_23%20-%20January%202017.pdf 3 | Improving stability in south-western NSW RIT-T – Project Specification Consultation Report Three types of credible options have been identified TransGrid considers there are three types of credible options that have the potential to meet the identified need from a technical, commercial, and project delivery perspective. These options cover: > a new or rebuild transmission line between Darlington Point and the new Dinawan substation being constructed for EnergyConnect (Option 1A (new line) and Option 1B (rebuild)); > a new transmission line between Darlington Point and Wagga Wagga (Option 2); and > a static synchronous compensator (STATCOM) solution (Option 3). Table E-1 summarises the credible options TransGrid proposes be assessed in the Project Assessment Draft Report (PADR). TransGrid notes that a STATCOM solution may not be able to relieve the constraint in full, due to the fast-acting nature of voltage collapse and the low system strength in the area. The benefits from this option are therefore likely to be less than those for the network options. Whether this option remains a credible option (or becomes non-economic) will be evaluated as part of the PADR. Section 4 of this PSCR provides detail on the technical characteristics that a non-network solution would need to have in order to assist with meeting the identified need for this RIT-T. TransGrid would be interested in hearing from proponents that provide these solutions. Table E-1: Summary of the credible options, $2019-20 Option Description Estimated capital Expected cost delivery time 1A Establish a new Darlington Point to Dinawan 330 kV $145-225 million 4-5 years transmission line 1B Rebuild the existing 99T Darlington